TV Glow

Introduction: TV Glow

This project details how to make a diffused light display out of electroluminescent, or "EL", panels and an old cathode ray tube television.

For this project I wanted to recreate the glow of a television without the dynamic and distracting snow. To do this I hollowed out the internals of an old CRT tv, and added my own light source using electroluminescent panels. Electroluminescent panels work in the same way that electroluminescent wire, or EL wire works in that they glow when a current is applied to their phosphor coating. Electroluminescent panels are often used as backlights for displays, and because I had some of these lying around, as well as their drivers, I used a few of each for this project. The electroluminescent panels were ideal for this application because they emit a diffused light rather than a point light source like LEDs (a spotlight pointed at you isn't the most relaxing thing).

This instructable will focus on the basics of the project as each electroluminescent panel will have it's own specifications and needs.

WARNING: I am not responsible for any injuries incurred during the making of this project, proceed at your own risk.

Step 1: Choosing the TV.

For this project you need a cathode ray tube TV, or CRT TV. CRT TVs are old/heavy TVs with a big ?booty? sticking out in the back. I suggest you pick one that has nice case and one with a screen size similar to your EL panel if possible (although I had to use multiple EL panels to fit across my screen, more on that later).

Step 2: Opening the TV.

CAUTION!!! Opening a CRT is very dangerous as high voltage can be stored in the tube or capacitors. There is really no way of going about it that doesn't assume some level of risk, but reading the following links will give you a decent guideline of what to do/be careful of. I am NOT responsible for any injuries you receive. If you are not sure of what you are doing, DON'T DO IT.

Open up the TV and remove any circuits that do not hold the front panel together. Disconnect and remove the tube and place in a small bag or box.

Step 3: Hammer Time

This step gets a little messy, so its probably best to do outside while wearing safety glasses, protective gloves, and a respiratory mask (these old TVs can contain some nasty particles). First you will want to release the vacuum on the CRT tube. BE CAREFUL, releasing the vacuum can cause the CRT to implode. Some way to insulate the tube in the event of implosion (such as some padding or a box) or a way to distance/protect yourself is advisable. The easiest way is to remove the nipple on the stem of the tube, or if there isn't one lightly tap a screwdriver into the stem of the tube. A light hissing noise will let you know you have released the vacuum.

Next you will want to remove a lot of glass from the stem side of the tube. As you can see in a few of the photos the front glass has a metal clip at each corner (where the front glass was mounted to the panel). You want to leave the front glass, and mounting clips in tact obviously. You will see a joint about an inch up from the clips where the back tube is joined to the front glass. Ideally you would like to smash all the back glass off to the joint so that you would have a clean front glass with no jagged edges, but RESIST the urge to break the glass all the way down to this point, as you will often end up with a cracked front glass and a wasted CRT.

Once you have removed most of the back glass, STOP. If you have some jagged edges you can sand them down at this point. Inside the tube you will see a metal screen, remove and discard this if it has not come out already.

Step 4: Remount the Front Glass.

Take the front glass and remount it in the case.

Step 5: Driving the EL Panels.

I am not going to get into the specifics of this because there are too many variations and I only did it this way because these are the components I had on hand. My recommendation is that you buy a power supply paired for your specific EL panel, but if you are dead set on going DIY the whole way you could design your own driver.

Here I am using a large power supply similar to those found in a desktop PC to feed three separate EL driver boards that came with the EL Panels (one for each of the three panels I am driving). At first I tried using only one EL driver but the brightness suffered, so I tied three drivers into the large supply. Ideally I would have liked to have one large EL panel that fits my TV's screen perfectly, but I didn't get THAT lucky, so I had to use three EL Panels taped together. Taping the three panels together didn't look so good, so I had to make some adjustments (see the next step).

Step 6: Finishing Touches.

Okay, so like I said before unfortunately I didn't have an EL panel large enough for my screen size so I had to tape three together. Although the three EL panels gave off a nice diffused light when taped together I could see the seem between the panels through the front glass. To fix this I cut tracing paper and put it in the front glass before placing my EL panels along the back. This made the light even softer and more diffused and also got rid of the visible edges between each panel.

Step 7: Donezo

After screwing the case back together the project is done. Check out the video to see it in action.

Thanks for looking.

Comments

I thought this project was going to involve using the intact tube itself to produce the light, not hacking the tube to replace everything with an electroluminescent panel. If you're just going to use an electroluminescent panel to replace most of the CRT (except the front glass) then why even bother smashing up the tube and risking poisoning from phosphor when you can just use the electroluminscent panel in a frame? I don't like this project.

Electroluminescent panels are not necessary for this. Modern cheap white LEDs very accurately replicate the nostalgic ~6400 K color temperature of old monochrome CRTs. You only need something to diffuse the light to evenly illuminate the screen.

Apparently, most of these screens contain lead (see http://en.wikipedia.org/wiki/Cathode_ray_tube#Toxicity). While I suppose my concerns might be unfounded, I would be VERY leery about doing anything (such as cutting, breaking, sanding, etc) to these old tubes that could release lead particulate into the air. I don't know if the lead being in glass makes it safe or not, but I would want to be absolutely certain about this before proceeding with this.

Your concerns are very valid. Personally, I would do TONS of research before opening ANY CRT (Cathode Ray Tube). . . .even outdoors, because your yard, pets, children would be exposed to this toxic contamination. AND someone downwind of you would be getting a load too.

Just because something exists, does not mean it is safe to disassemble. Even if you have the tools, ability to use them and curiosity, does not mean you are invincible.

Lots of people think it is safe to even break a CFL (Compact Fluorescent Lamp) light bulb, and merely sweep or vacuum it up. It's not.

Cool project, but I hope anybody considering it will thoroughly research what possible toxic exposures they are dealing with.

The method for "safeing" explained involves handling where an accident could happen. Here is an easier and safer way to do it. First, place the TV face down on a carpeted surface. Remove the back of the case. Discharge the CRT as described. Stuff an old sheet or rags between the outside of the CRT and the inside of the case, covering everything except the very back of the neck. If the CRT implodes during the following steps, the sheet will totally contain it. Remove the socket (and its usually included circuit board) from the back of the CRT. If the "teat" is exposed, hold #2 phillips screwdriver vertically 1/4 inch above the teat. Tap sharply on back of screwdriver with smallest hammer (the trick is to have the hammer propel the driver which hits teat). Use gradually harder hits until teat cracks. Wait for hissing to stop. To be sure, punch completely through teat with hammer/driver. (If plastic socket covers teat, remove that totally or remove center part only exposing teat first.) Remove sheet/rags. Remove deflection yoke assembly. Using old file, make a scratch 1/2 way around the neck just behind where the flare begins. Wet rag, wipe scratch. Wrap neck in rag (1 layer only). Using "engineering hammer" (5 lb head, like small sledge) tap neck sideways at the very back, from the side the scratch is on). Neck will cleanly snap off at the scratch. The secret to this step is to have a very heavy hammer moving slowly. The flare of the CRT is best broken off with the CRT held face-up, outside, over a garbage can, while still mounted in the case, if possible, while wearing safety glasses and heavy gloves as explained. Use a heavy hammer moving slowly. This way, the glass will not tend to fly so much.

Every CRT I've seen has a thin tube sticking out the ring of pins. It's *designed* to be broken off the vent the tube without implosion. Putting the tube in a box with just that part of the neck sticking out is a sensible precaution -- but then throwing a brick at it is silly. Just nick the vent tube with a file and give it a tap with pliers.

Better, still, why not use the tube as it was originally intended? Massively defocus the beam with a fixed video level input, and you'll get your CRT glow.

Also to consider. The phosphors used in old TV tubes were sometimes quite nasty and contained barium, lead and other bad stuff. Since these were normally sealed up inside the tube there was no problem but breaking it apart releases bad agents as dust. I would really consider the plexiglass approach or at least doing this outside of living areas and spraying clear plastic coating on the now exposed screen back to seal it up.

Having seen picture tubes implode violently more that once, I suggest that, instead of using the picture tube, use a piece of frosted Plexiglas or Lexan cut to the proper size and glue it in. It will be just as effective and much, much safer.

CRTs are under very high vacuum & can implode when broken, violently. If you must do this, the safest method I have found is to put the tube in a cardboard box & duck tape the box all over, with just the tip of the neck sticking out. I then stand back & throw a brick or rock at the exposed end breaking the neck off. BE SAFE !!

I used to work in a TV repair shop back in college. The way we'd relieve the vacuum was to break the little teat off the back of the tube. You'll find it under the electron guns in teh back center of the tube. A quick squeeze with a pair of needle nose pliers and you'll hear it.